1. Field of the Invention
This invention relates to a vehicle for use underground more particularly, to a self-propelled, multipurpose vehicle for use in underground mining operations.
2. Description of the Prior Art
Underground mining operations, particularly in the coal industry, have come under increased scrutiny by governmental agencies and the general public because of the safety hazards presented to workers in the mines. Some of these hazards are inherent in the nature of underground mining itself; for example, the threat of a roof cave-in or the possibility of a build-up in gas or dust concentrations in the mine and a resulting explosion. Other of the hazards are created by inadequacies in equipment being used at the present time in an attempt to meet governmental regulations imposed because of the existence of the inherent hazards. A brief description of a typical underground mining operation carried out in today's coal mines will bring these equipment insufficiencies into focus:
A coal mine comprises a network of shafts and rooms excavated along the course of coal veins. Headroom in these shafts and rooms is ordinarily restricted depending upon the thickness of the particular vein and may vary between about 4 to 10 feet. Thus, low profile equipment is essential in most mines.
A machine known as a continuous miner is the primary piece of equipment used to extract coal from the vein. This machine works at the fresh, exposed face of the coal vein, loosening the coal by the action of movable augers. Mechanical arms mounted on the machine sweep the loosened coal to the rear of the machine as it progresses forwardly against the face. The bulk of this coal is picked up by suitable means and conveyed out of the mine. As the continuous mining machine advances, it creates an expanse of ceiling or roof which is unsupported and subject to collapse. Accordingly, the forward travel of a continuous miner under an unsupported roof is restricted by government regulation. When the appropriate limit of forward travel is reached, the continuous miner must retreat from the face of the mine until the roof has been suitably supported.
Roof support is achieved in most coal mines by installing metal bolts in the roof at spaced intervals fixed by government regulation. The required spacing of bolts will depend on the width of the room but ordinarily is 4 feet both transversely and longitudinally. Installation of a roof bolt involves first the drilling of a hole in the roof, the insertion of a bolt having an expander of any well known type at the end, and finally torqueing the bolt to a predetermined value. Roof bolt installation is complicated by the fact that the government regulations prohibit mine personnel from working under an unsupported roof. Further problems are created during the roof bolting operation by government regulations requiring that any loose debris left by the continuous miner be cleaned from the mine floor as soon as possible.
Present coal mine practice involves the use of a machine known as a roof bolter for installing roof bolts. Generally, a roof bolter comprises a mobile platform having a movable boom extending therefrom. A drill head is mounted at the end of the boom and is controlled by a workman standing nearby. Usually, the workman actuates the drill with one hand and guides the shank of the upwardly moving drill bit with the other hand. The proximity of the workman to the drill has been the source of many serious accidents in the mines; for example, the drill bit may break or a drill bit extension may become disconnected and, in either case, strike the workman standing nearby. The drilling operation usually causes dust and debris to fall from the roof, hindering the workman's vision and otherwise endangering his health and safety.
Similar dangers are created by the existing method of inserting roof bolts. In most cases, the required length of the roof bolt is such that the bolt must be bent to start it into the hole drilled in the roof. The bending operation is done manually and with relatively little effort by the workman because of the flexibility of the metal used in conventional roof bolts. The head of the bolt is then inserted in the socket of the drill head and the bolt is driven home by the upward stroke of the drill head. Again the workman must control the movement of the drill head with one hand and guide the bolt with the other, thereby subjecting him to the danger of being hit by an errant bolt. Also, the insertion of the bolt causes dust and debris to fall from the roof, thereby creating the same hazards discussed above with respect to the drilling operation.
Following the insertion of bolts in an unsupported roof, conventional practice calls for the roof bolter to be withdrawn so that a machine with a scoop mounted on the front may enter the newly supported area to remove loose debris in accordance with regulations discussed above. Once the scoop is loaded, the machine must be backed away from the mine face until it reaches a cross-shaft where it can turn around and continue its movement to an unloading site. All of these operations are time consuming and reduce the productivity of the mine.
The present invention overcomes the disadvantages and objections associated with present roof bolting equipment and methods. Not only are personnel safety hazards markedly reduced, but also more efficient operating procedures are afforded by the present invention.